​​This book provides standards and guidelines for
quantifying greenhouse gas emissions and removals in smallholder agricultural systems
and comparing options for climate change mitigation based on emission
reductions and livelihood trade-offs. Globally, agriculture is directly
responsible for about 11% of annual greenhouse gas (GHG) emissions and induces
an additional 17% through land use change, mostly in developing countries.
Farms in the developing countries of sub-Saharan Africa and Asia are
predominately managed by smallholders, with 80% of land holdings smaller than
ten hectares. However, little to no information exists on greenhouse gas
emissions and mitigation potentials in smallholder agriculture.  Greenhouse gas measurements in agriculture
are expensive, time consuming, and error prone, challenges only exacerbated
by the heterogeneity of smallholder systems and landscapes. Concerns over
methodological rigor, measurement costs, and the diversity of approaches,
coupled with the demand for robust information suggest it is germane for the
scientific community to establish standards of measurements for quantifying GHG
emissions from smallholder agriculture. Standard guidelines for use by
scientists, development organizations will help generate reliable data on
emissions baselines and allow rigorous comparisons of mitigation options. The
guidelines described in this book, developed by the CGIAR Research Program on
Climate Change, Agriculture, and Food Security (CCAFS) and partners, are
intended to inform anyone conducting field measurements of agricultural
greenhouse gas sources and sinks, especially to develop IPCC Tier 2 emission
factors or to compare mitigation options in smallholder systems.